Bed heater



W. J. MILLER June 7, 1949.

BED HEATER 2 Sheets-Sheet 1 Filed Dec. 4, 1947 f/a. I;

June 7, 1949. w. J. MILLER 2,472,224

BED HEATER Filed Dec. 4, 1947 2 Sheets-Sheet 2 INVENTOR. WAI. rze J.MUM-'2.

Patented June 7, 1949 UNITED STATES PATENT OFFICE BED HEATER Walter J.Miller, South Bend, Ind.

Application December 4, 1947, Serial No. 789,603

This invention relates to improvements in bed heaters, and particularlyto heaters usable by persons confined to bed with tuberculosis orpulmonary diseases requiring fresh air treatment. During cold weathersuch bedridden persons must use some type of a heater to provide anexternal source of heat to prevent discomfort and objectionable chillingof the body. To be fully satisfactory a heater of this character mustpossess various properties. Thus its shape and size must be such as topermit it to be positioned near different parts of the body of thepatient. It must provide protection against overheating or burning ofeither the patient or the bed clothing, and it must provide forcirculation of air therearound.

The primary object of this invention is to provide a device which servesthe purpose and satisfies the requirements mentioned above.

A further object is to provide a device of this character with a frameformed from insulating material and constructed for free circulation ofair between the outer portion thereof and a heatgenerating portionpositioned interiorly thereof.

A further object is to provide a device of this character with a cagewithin which is positioned a housing adapted to receive aheat-generating element, said element being removably mounted andsupported in fully insulated relation to the cage, and the housing beingspaced inwardly from the grill or open portions of the cage.

A further object is to provide a device of this character with novelhumidifying means.

A further object is to provide a device adapted to be placed in aplurality of angularly related positions and including a heating chamberwith a plurality of openings, each provided with a pivoted closuremember, wherein said closure members are so constructed and positionedthat one thereof will open automatically to provide for air circulationin the heating chamber in each of the positions in which the device maybe placed.

A further object is to provide a device of this character withtriangular end members which are interconnected by spaced bars or grillsand which support therebetween a heating chamber spaced inwardly fromsaid bars and removably receiving a heating element, wherein all exposedor external parts of the device are formed of insulating material.

A further object of the invention is to provide 14 Claims. (Cl. 219-38)Other objects will be apparent from the following specification.

In the drawing:

Fig. 1 is a view of the device in side elevation.

Fig. 2 is an end View of the device looking toward the right in Fig. 11

Fig. 3 is a longitudinal vertical sectional view taken on line 3-3 ofFig. 2.

Fig. 4 is a transverse vertical sectional view taken on line 44 of Fig.1.

Fig. 5 is a transverse sectional view of a humidifying attachment.

Fig. 6 is an enlarged sectional detail view of a portion of thehumidifying attachment.

Referring to the drawings which illustrate the preferred embodiment ofthe invention, the numeral NJ designates two similar and frame memberswhich are preferably of triangular form and are provided with centraltriangular openings I2 of substantially the same shape as the outertriangular shape of the frame members. As best seen in Fig. 2, the framemembers [0 are of a shape in which the three sides thereof are ofdifferent lengths so that the two upstanding sides thereof in each ofits three possible positions resting upon a third side will extend atdifferent angles relative to the vertical. The points or corners of theframe members are preferably rounded at I4, and the edges of the framemembers are also preferably rounded so that no sharp edges occur. Themembers H) are preferably formed of wood although they may be formed ofother insulating material such as a thermosetting plastic. The primaryrequirement of the material of which the members III are formed is thatthe same provide good insulation against both heat and electricity. Inother words, the material of which members 10 is formed should be adielectric material and it should possess a high resistance to thetransfer of heat therethrough.

The two end members ID are rigidly interconnected by a plurality of rodsor bars 16, each fixedly secured or anchored at its opposite ends to theframe members [0. The bars or rods at the corners may be larger than theremaining bars and each thereof should be of substantial strength andformed of wood, thermosetting plastic material or other material whichpreferably has the same properties of insulation against heat transferand against electric current as described with respect to frame membersIll. The bars or rods 16 are preferably arranged in parallel relationperpendicular to the frame members I0 and spaced apart substantiallyuniformly. The preferred spacing of the bars or rods preferably does notexceed three-fourths of an inch, although this spacing is optional. Thedevice is made of such a size that a plurality of bars, as bestillustrated in Fig. 4, span the two end members 16 adjacent each of theedges thereof. The rods l6 are preferably spaced inwardly slightly fromthe edges of the frame members I and are spaced from the inner edges l2of said frame members a greater distance, as best seen in Fig. 4.

A tubular member 118 is mounted at its Opposite ends within the openingsl2 of the end members to span the same and define an open ended heatingchamber. The member [8 is preferably formed of sheet metal, is securedto the end members i ii in any suitable manner, and is of acrosssectional shape conforming to the shape of the openings l2. As hereillustrated, the chamber 16 is of triangular cross-section with its sidewalls substantially parallel to and equispaced from the marginal edgesof the frame members I 0 and the bars [6. One end of the chamber 48 isspanned by a closure panel 20 provided with :a plurality of apertures 22formed therein toreg-ister with the interior of the casing member L8.The closure 26 is formed of a noncond-ucting material, such as wood,thermoplastic material or composition material of the character commonlyknown as hardboard. The panel 20' preferably bears against spacers 24which -.eng ag-e the outer faces of one of the end members '0 and issecured to the end member by securing. members 26. Thus the end of thedevice provides a plurality of paths for air circulation into andoutofthe heat chamber It, the same constituting the openings '22 in the panel26 and the space, best illustrated in Figs. 1 and 8, which separates thepanel 20 from the adjacent end member. Additional openings for passageof air into and out of the chamber l3 may be provided in spaced reiationto the end panel 2!]. As here illustrated, the tubuiar chamber member ismay :be provided with :a plurality of openings 2.8 in itsside wallswhich are of substantially the same size :as the openings 22 in thepanel 20, and each side wall of the panel may be further provided with acomparatively large opening -36 positioned substantially centrally ofthe length of themem-ber 1 8. The openings scare preferably of the shapebest illustrated in Fig. 4 providing a large primary opening from whicha reduced portion projects longitudinally. This reduced port-ion may bedefined in part of the space provided by bending; -a portion of thematerial of the member t8 to define an integral outwardly projectingcylindrical part 32, as best shown in Fig. 3, which defines a hingesocket. A sheet metal closure'plate 34 spans each aperture 36, bearingat its margin upon the surface of the wall of the chamber L8 around theopening 36 and being provided with :a tongue which .fits =ro-- tatablywithin the cylindnioalsocket 32 and provides a pivot axis or hingeiflintle to which the plate 34 may be pivoted. It will be understoodthat the shape of the opening "and the shape and hinge construction ofthe pivoted closure, as herein defined, .is illustrative only and thatany other shape and constructionof these parts which will permit thepivotal mounting "of a closure to span the opening at, the outer surfaceof the tubular member 1-8 which isfound suitable, may be employed in thedevice. It will be observed from Figs. 1 :and 3 that the construction issuch that the closures :34 will be positioned by gravity. Consequentlythe lowermost opening 36 will be opened by the pivotal opening of theassociated closure 34 by gravitmiand the remaining openings 36 will beclosed because of the upward and inward inclination of the wall portionsin which said openings are formed, which provides for the action ofgravity upon the closure 34 of said openings in a direction to close thesame. This permits the intake of air into the chamber within the tubularmember 18 from its bottom, and the remaining openings, such as theopenings 22, 26 and the space between the members It and '28 provide airoutlets, thus permitting the circulation of air surrounding the heaterby convection flow. It will be apparent that the triangular shape of thedevice, when made in an effective size entailing a height in the Fig. 2position of approximately 6 to 10 inches, will hold the bed covering orblankets spaced above the mattress to provide an air space in which thecirculation can occur. Furthermore, it will be apparent that, even incases where the bed covers are fitted closely around the device, thespace between the bars 16 and the heat chamber will provide .an aircirculating space.

The end of the tubularmember l8 opposite that spanned by the plate 2.61sspanned and closed by a panel 36 which is formed of a dielectricmaterial having heat insulating properties, such as wood, thermosettingplastic material. or composition board. The panel 36 issecured to theframe member Ill by the securing members 36, such as wood screws, and,if desired, may be spaced from the member iii by the use of spacers inthe same mannor in which panel 20 is spaced from the end member It. Thepanel 36 is preferably strong and rigid and is adapted to provide asupport for a carrier which. mounts an electrical heating element andother electrical parts used in conjunction with a heating element. Inthe form illustrated, the carrier comprises a rigid U-shaped bracketwhich may be formed of metal or any other suitable material having anarm 40 which is clamped against the panel 36 by a rigid panel 42 whichmay be formed of some dielectric material, such as composition board orhardboa-rd. The panel 52 is held in clamped relation to the panel 36 bysuitable securing means, such as bolts and nuts 54. The base 46 of theU-s-haped carrier is so positioned that .it is spaced from and clear ofthe metal tubular sheath [8 in its operative position, as best shown inFig. 3. This base preferably mounts a block 18 of an electric insulatingmaterial, such as asbestos, rubber, thermosett-ing plastic material, orthe like. A pilot heating element 56 is supported upon the block 48 andsecured in operative position thereto by .a retainer, such as a band 52passing around the base 46 and the element 50. The inner leg 54 of thecarrier preferably extends substantially parallel to the leg 4b inspaced relation thereto, and a block 56 of insulating material bearsagainst one face thereof. A second block of insulating material 58 ispositioned parallel to the block 56 and is backed by the rigid housingof a thermostat 66. Securing members 62, such as bolts and nuts, serveto clamp the thermostat and the leg 54 in position to grip between theblocks 56 and 58am electrical heating element 64 of any suitable typeand construction. As here illustrated in Fig. 4, this heating elementcomprises a flat annular member formed of electrical resistance materialadapted to generate heat when current is passed therethrough. Suitableelectrical connections (not shown) are efiected between the terminals 66of the thermostat 66 and the heating element. Electrical leads 68connect the terminals 66 with terminals 16 carried by the panel 42, anda three-wire electrical cord 12 has its wires connected to the terminalsill and the terminals of the element 50 in circuit controlling relation,as well understood in the art. The electrical cord 12 is preferably anelongated flexible sheathed and insulated cord which passes through anopening in the panel 36 and through a lead-in socket of conventionalconstruction carried by the outer surface of the panel 36 and servingthe purpose of preventing kinking of and damage to the electrical cord.As here shown, this socket is formed of rubber or other flexibleinsulating material and has an enlarged base flange 14 of a size tooverlie the securing'members 44, the terminal and other parts anchoredto the panel 36, and has a tubular extension 16 through which the cord12 extends and by which the cord is positioned. The cord will beprovided with a suitable selector switch (not shown) intermediate itslength which may be positioned within the reach of the patient in allpositions of the heater to permit the patient to energize or deenergizethe heating elements 50 and 64 and which may further include pluralsettings for selectively controlling the circuits to the individualheating elements. Selector switches of this type are commonly known inthe art and do not form a part of this invention, and for this reasonhave not been illustrated herein.

It will be observed that the construction and arrangement of theelectrical parts and their mounting upon a common support, namely thepanel 35, facilitates the assembly and disassembly of the device andmakes possible the removal of the heating element by disconnecting thepanel from the remainder of the device. struction is such that all ofthe electrical parts are held in fixed relation to each other and to thepanel 36 so that all danger of short circuit is avoided and yet fullaccess for repair and replacement of parts is afforded.

By reason of the shape of the device, as best illustrated in Fig. 2,wherein the sides of the triangle are of different lengths and atdifferent angles, it is possible to position the heater closely adjacentto any part of the body Without discomfort to the user. The formation ofthe outer cage of the device, constituting the end members It), thepanels 35 and the bars Hi, from dielectric material having a low heatconductivity permits the device to be positioned directly in contactwith the body of the patient without danger of injury due either toelectrical shock or to excess heat. Thus it is possible to place theheater for engagement of the feet of the patient therewith, place itagainst the side or back of the patient, or in any other position wherethe source of heatis desired. The device can be positioned at any angleselected so that comfort is assured, for instance, at such an angle thatthe soles of the feet may press comfortably against the bars IS withoutrequiring the feet to be held in an uncomfortable position. Aircirculation and the transfer of heat under the bed covering around thebody of the patient is assured by the convection flow of air to andthrough the heater, the cage insuring that the bed covers will not closethe air passages communicating with the heating chamber. In thisconnection, the air will always be drawn into the heating chamberthrough the bottom by virtue of the automatic opening by gravity of theclosure 34 which is positioned lowermost in the device. These featuresand other advantages of the device render it particularly satisfactoryfor its intended use by bedridden patients, render it safe for such use.and permit its use with comfort.

The con- The use of a bed heater of this particular type over anysubstantial period of time will cause the air being heated thereby to bedried, thereby lowering the humidity of the air around the patientsbody. This has an adverse effect upon the skin, tending to dry out theskin and cause discomfort. Forthis reason it may be desirable in mostinstances to provide humidifying means within the device, particularlywhere the device is used by bedridden individuals.

Such humidifier has been illustrated in Figs. 3, 5 and 6 and includes apair of end members of a size and shape to fit snugly and slidablywithin the tubular portion l8 of the heater. These end members are rigidand are connected together by longitudinal bars or rods 82 and arespanned by a tubular absorbent member 84. The end members 80 havecentral openings 86 therein, defined in part by integral cylindricalwall portions 88 around which the opposite ends of the absorbent tubularpart 84 fit. An outer circular rib or flange 90 concentric with thecylindrical flange 88 fits around the outer ends of the absorb entmember 84. The construction is rigid and may easily be inserted into andremoved from the tubular part 18 of the device. In cases Where thehumidifier is utilized, the end panel 20 may be omitted if desired,particularly if means are provided for positioning the humidifier in thedevice. Such means may comprise spring clips 92 adapted to engage andhold the outermost panel 89 detachably in selected position.

The absorbent tubular member 84 may be of any suitable construction, itbeing desirable, however, that such member will not lose its containedmoisture by a dripping action. Thus, if desired, a porous refractorymember may be employed. Such refractory members have limitedwaterabsorbing capacity, and I prefer to employ a construction of thecharacter best illustrated in Fig.

6, wherein a thin flexible corrugated metal sheet 94 has adhered theretoan absorbent fibrous sheet member 93, such as a sheet of asbestosmaterial. This built up sheet, comprising the non-corrosive flexiblemetal backing and the absorbent fibrous sheet 94, may be rolled intotube form providing a plurality of laminations, as illustrated in Fig.6. The arrangement is preferably such that the metal sheet 94 will bepositioned outermost and the absorbent sheet 93 will be positionedinnermost and will be encircled by a tube 95 cemented at its ends to theflanges 90. A device of this character, where the end members are formed of material such as a plastic or non-corrosive metal, may beimmersed in a body of water to absorb an amount of liquid therein up tothe level of the line 96 in Fig. 5. This will be adequate to providesaturation by an amount of water which will supply the desired humidityfor a substantial period or time. The amount of Water absorbed shouldnot be greater than that which is retained by one of the cylindricalflanges 88 when the humidifier is positioned on end. In this connectionit will be apparent that air entering the device from the end will passthrough the tubular absorbent member 84 to pick up the moisture of thewetted inwardly facing porous lamination 93 for the desired amount ofmoisture transfer to the air.

This humidifying device is an attachment Whose use is optional and whichavoids all disadvantages and hinderances to the use of humidifiers. Thusthe enclosure of the humidifier within the device prevents thepossibility that the bed clothing will be wetted by the humidifier,

- the construction of the absorbing agent avoiding all danger ofdripping of water from the humidifier. Likewise, no danger of electricalshock is entail-ed despite the use of an electrical heating element inthe presence of a humidifier because the manufacture of the end plates8t of the humidifier from a plastic, such as a thermosetting phenolicplastic, will avoid all danger of transmission of electrical shock tothe user or to the sheath I8.

While the preferred embodiment of the invention has been described andillustrated herein, it will be understood that changes maybe made in theconstruction within the scope of the appended claims without departingfrom the spirit of the invention.

I claim:

1. A bed heater comprising a pair of similar end members, each having aplurality of angularly disposed flat end portions, a plurality of spacedbars connecting the marginal portions of said end members, an open endedtubular member spanning and secured to said end members in inwardlyspaced relation to said bars, a pair of closures carried by said endmembers and spanning the ends of said tubular member, said tubularmember and at least one closure having passages for air circulationthrough said tubular member in one or more laterally dischargingpredetermined paths, and an electrical heating element carried by oneclosure and positioned with in said tubular member.

2. A bed heater comprising a pair of similar and members, each having aplurality of angularly disposed fiat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning the ends of said tubular member, saidtubular member having apertures therein at portions substantiallycentrally located relative to the planes defined by said fiat edgeportions, and an electrical heating element carried by one closure andpositioned within said tubular member, said end members, bars andclosures being formed of a dielectric material having a low heatconductivity.

3. A bed heater comprising a pair of similar end members, each having aplurality of angula-rly disposed flat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning the ends of said tubular member, at leastone of said closures being spaced from the end member which mounts itand from said tubular member, and an electrical heating element carriedby one closure and positioned within said tubular member, said tubularmember being of a cross-sectional shape substantially similar to theshape of said end members and having substantially fiat portionsprovided with apertures therein substantially centrally located betweenthe longitudinal edges defining said fiat portions, each of said barsbeing spaced from said tubu lar member substantially the same distance.

4, A bed heater comprising a pair of similar end members, each having aplurality of angularly disposed flat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning, the ends of said tubular member, and anelectrical heating element carried by one closure .and positioned withinsaid tubular member, said tubular member and at least one closure eachhaving an aperture therein for the passage of air into and out of saidtubular member, the apertures in said tubular member being locatedspaced below the uppermost portion thereof in all positions of saidheater.

5. A bed heater comprising a pair of similar end'members, each having aplurality of angularly-disposed flat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning the ends of said tubular member, and anelectrical heating element carried by one closure and positioned withinsaid tubular member, said tubular member having a plurality of openingstherein each in a portion thereof adiacent to a fiat edge of said endmembers, and a closure adapted to span each opening and hinged to saidtubular member to pivot to open position when the adjacent flat edge ofsaid end members bears on a support.

6. A bed heater comprising a pair of similar end members, each having aplurality of angularly disposed flat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning the ends of said tubular member, and anelectrical heating element carried by one closure and positioned withinsaid tubular member, said end member being of triangular form with theedges thereof of different lengths and positioned in acute angledrelation.

7. A bed heater comprising a pair of similar end members, each having aplurality of angul'arly disposed fiat edge portions, a plurality ofspaced bars connecting the marginal portions of said end members, anopen ended tubular member spanning and secured to said end members ininwardly spaced relation to said bars, a pair of closures carried bysaid end members and spanning the ends of said tubular member, and anelectrical heating element carried by one closure and positioned withinsaid tubular member, the closure opposite that which mounts said heatingelement being a-pertured and being mounted in outwardly spaced relationto the adjacent end member, said tubular member having apertures thereinspaced from said last named aperture and spaced below the uppermost partof the tubular member in all positions of the heater.

8. A heater comprising a cage structure defined by end members and barsinterconnecting said end members, a housing supported within said cageand spaced inwardly relative to said bars, a heating element enclosedwithin said housing, said cage having a plurality of 'angularly disposedsupporting surfaces, said housing having a plurality of apertures, andclosures pivoted to said housing adjacent selected apertures, oneclosure being located adjacent each supporting surface, the lowermostclosure being adapted to swing to open position by gravity.

9. A heater comprising a cage structure of triangular shape incross-section and having grilled sides and end closures, a housingcarried by said structure spaced inwardly relative to the grilled sidesthereof, said housing defining a heating chamber and having aircirculating apertures in each side and at least one end thereof, aheating element within said chamber, and closures pivoted to saidhousing and each adapted to span one of said side apertures and to swingby gravity to open position when positioned lowermost.

10. A heater comprising a cage structure of triangular shape incross-section and having grilled sides and end closures, a housingcarried by said structure spaced inwardly relative to the grilled sidesthereof, said housing defining a heating chamber and having aircirculating apertures in each side and at least one end thereof, aheating element within said chamber, and closures pivoted to saidhousing and each adapted to span on of said side apertures and to swingby gravity to open position when positioned lowermost, said heatingelement being an electrical resistance element, said cage having aremovable end member, and means carried by said removable end member formounting said heating element.

11. A bed heater adapted to be positioned beneath the covers of a bedcomprising a cage structure defined by end members and barsinterconnecting said end members, a housing carried by said end membersin inwardly spaced relation to said bars, a heating element enclosedwithin said housing, said end members and housing having air circulatingapertures therein, and a humidifier detachably mounted in said housing.

12. A bed heater adapted to be positioned beneath the covers of a bedcomprising a cage structure defined by end members and barsinterconnecting said end members, a housing carried by said end membersin inwardly spaced relation to said bars, a heating element enclosedwithin said housing, said end members and housing having air circulatingapertures therein, and a humidifier detachably mounted in said housing,said humidifier comprising a pair of spaced apertured end panels, and aporous tubular member carried by said panels with its bore communicat- 4ing with said panel apertures.

13. A bed heater adapted to be positioned beneath the covers of a bedcomprising a cage structure defined by end members and barsinterconnecting said end members, a housing carried by said end membersin inwardly spaced relation to said bars, a heating element enclosedwithin said housing, said end members and housing having air circulatingapertures therein, and a humidifier detachably mounted in said housing,said humidifier comprising a pair of spaced apertured end panels, and aporous tubular member carried by said panels with its bore communicatingwith said panel apertures, and a spring retainer carried by said housingand engageable with an end panel.

14. A heater comprising a cage structure defined by end members and barsinterconnecting said end members, a housing carried by said end membersin inwardly spaced relation to said bars, a heating element enclosedwithin said housing, said end members and housing having air circulatingapertures therein, and a, humidifier det'achabiy mounted in saidhousing, said humidifier comprising a pair of spaced apertured endpanels, and a porous tubular member carried by said panels with its borecommunicating with said panel apertures, said end panels each having anannular flange around the aperture thereof, and said porous membercomprising a plurality of convolutions of a laminated structure, eachlamination including a corrugated sheet of metal and an absorbentfibrous sheet adhered to the inner face of said metal sheet.

WALTER J. MILLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,957,576 Brasic May 8, 19342,258,944 Bethell Oct. 14, 1941 FOREIGN PATENTS Number Country Date158,988 Great Britain Feb. 14, 1921 558,564 France May 28, 1923

